It is 9pm in January. The air conditioner has been running since lunch, the bedroom windows are open, and the ceiling is still warm to the touch. Most people blame the weather. The real culprit is usually sitting on top of the house.
A roof takes the full sun from mid-morning to late afternoon. A dark roof absorbs a large share of that energy and passes it down into the roof space, and from there into the rooms below, long after the sun has gone. You cannot change the weather. You can change what your roof does with it, and that is what a reflective roof coating is for.
What a reflective roof coating actually does
Every roof surface either absorbs sunlight or bounces it back. A reflective coating tips that balance. Prominent Paints Neuklad Cool Roof is formulated to reflect up to 30% of solar heat, so less of the sun’s energy ever gets into the roof sheet or tile in the first place. Less heat in the roof means less heat working its way into the ceiling.
Two things are worth being clear about. First, reflectance is a property of the coating. How much cooler your rooms feel depends on your ceiling insulation, ventilation and roof construction, so we do not promise a fixed temperature drop. Second, a cool roof is not only about comfort. A roof that runs cooler expands and contracts less through the day, which is easier on the coating, the fasteners and the sheeting underneath. That is a longer-term saving most people never see, because nothing goes wrong.
Neuklad Cool Roof is also formulated for UV and water resistance with good flexibility, which matters in a climate that swaps blazing sun for a highveld thunderstorm in the same afternoon. It is a roof coating first and a heat reflector second, and it needs to be both.
Know your roof before you buy anything
The single most useful thing you can do before a roof project is to work out what your roof is made of. Cement tiles, fibre cement sheets, galvanised steel and Chromadek all take the same top coat, but each one needs a different preparation and primer underneath it. Get that wrong and the best coating in the world will let go within a season.
Then look at the condition. Walk the roof, or get someone who can do so safely, and look for cracked or broken tiles, loose fasteners, rust bleeding from screw heads, lifting laps on the sheeting and any sign of a leak inside the ceiling. Every one of those needs fixing before a coating goes on. A coating protects a sound roof. It does not repair an unsound one.
A word on safety, because it is the part of roof work that gets skipped. Plan how you will get up and down, use a stable ladder or scaffolding, and do not work alone or in wind. If the pitch is steep or the sheeting is old, this is a job for a contractor.
Cleaning and preparation
Most roof coating failures start with what was left on the roof before the paint arrived. Algae, moss and fungus are the usual suspects on the shaded side, and a fresh coat will not bond to them. For cement tiles the Neuklad Cool Roof data sheet calls for Prominent Paints Fungal Wash to kill the spores and stop regrowth. Rinse thoroughly afterwards and let the roof dry completely.
Next comes the loose material. A high-pressure wash or a stiff scrub takes off chalking, dust and dirt. If you rub the old surface and it leaves powder on your hand, that powder has to come off, because new paint bonds to whatever is underneath it. Fill cracks and repair defects so the surface is stable and uniform.
Then wait for the right day. Do not coat in high humidity or in the cold, because both interfere with adhesion and curing. A roof that looks dry can still be holding moisture in a porous tile, so give it time after washing. The prep is unglamorous, and it is where the job is won.
Priming and applying the coating
Whether your roof needs a primer depends on the substrate and its condition. Bare galvanised steel needs a metal primer to stop corrosion getting under the coating. Porous cement surfaces need a penetrating primer to give the top coat something to grip. The Neuklad Cool Roof data sheet has a substrate preparation table that sets out the correct system for each roof type, and your nearest Prominent Paints store will match it to your roof if you take a photo along.
Once the primer is done, stir the Neuklad Cool Roof thoroughly and apply two coats, following the recoat interval on the tin. The system is designed to build around 60 microns of dry film per coat, about 120 microns across two coats, and that thickness is part of how it does its job. Stretching a tin to save a litre costs you the protection you were paying for.
Work in the cooler part of the day. Never paint onto sun-heated metal or a damp surface. A sheet roof at midday in summer is hot enough to flash-dry the coating before it has bonded, and you will see the result within the first year.
Working with South African weather
The weather window is more forgiving than people expect, as long as you plan around it. Aim for moderate, dry conditions, roughly 16 to 28 degrees, and avoid high humidity or painting late in the day when dew is about to form. In summer, start early and follow the shade to avoid flash-drying. In winter, aim for late morning to mid-afternoon when the roof has warmed up.
Buying the right amount matters as much as the timing. The Prominent Paints Roof Paint Calculator at www.prominentpaints.co.za/roof-paint-calculator estimates what you need from your roof area and profile. Add 5 to 10% for wastage and touch-ups, and buy for the full two coats before you start rather than running out halfway across a slope.
One last choice. If maximum reflectance is not your top priority and you want one coating for both the roof and compatible paving, Prominent Paints Premium Roof and Paving is a versatile, lead-free alternative for galvanised and cement tile roofs. If the goal is a cooler house, Neuklad Cool Roof is the one built for it.
Frequently asked questions
Will a cool roof coating make my house noticeably cooler?
It reduces how much of the sun’s heat gets into the roof in the first place, which is where a hot house starts. How much difference you feel indoors depends on your ceiling insulation, ventilation and roof construction, so we do not promise a fixed temperature drop. Homes with little or no ceiling insulation tend to notice the change most. Think of it as taking heat out of the system at the source.
What colour can I paint my roof and still get the cooling benefit?
Lighter colours reflect more heat, which is why Neuklad Cool Roof is supplied in light colours rather than tinted dark. Tinting a reflective coating to charcoal or dark green reduces the reflectance and defeats the point of the product. If you want a darker roof for the look, Premium Roof and Paving is the better product to talk to your store about. If you want a cooler house, keep the roof light.
Can I put Neuklad Cool Roof straight onto my old roof?
Not without preparation. Algae and fungus need to be killed with Fungal Wash and rinsed off, loose and chalky material needs to be washed or scrubbed away, and cracks and defects need repairing first. Depending on the roof type and condition, a primer may also be required. The data sheet substrate table and your local store will confirm the right system.
Which primer does my roof need?
It depends on what the roof is made of. Bare galvanised steel needs a metal primer to prevent corrosion, and porous cement tiles need a penetrating primer for adhesion. Fibre cement and Chromadek each have their own requirements. Take a photo of your roof and a close-up of the surface to your nearest Prominent Paints store and they will specify the primer for you.
How many coats do I need and how much paint should I buy?
Two coats is the standard system, building to around 120 microns of dry film in total. Use the Roof Paint Calculator on the Prominent Paints website to estimate the quantity from your roof area and profile, then add 5 to 10% as a margin for touch-ups and wastage. Buy the full amount before you start so both coats come from the same batch.
When is the best time of year to coat a roof in South Africa?
Spring is ideal, before the summer heat and storms arrive, because the roof is dry and temperatures are moderate. Aim for dry days between roughly 16 and 28 degrees, avoid high humidity, and never coat a roof that is baking in midday sun or still damp from rain or dew. In summer, work early in the morning and follow the shade. A roof coated in October is protecting the house before the first real heat of December.
Get the roof ready before summer does
A cooler roof is one of the few home improvements that pays you back every hot afternoon. Sort the roof first, prepare it properly, put the full two coats on and keep it light, and the house underneath gets easier to live in.
Before you start, visit your nearest Prominent Paints store with photos of your roof. The team will confirm the right primer and system for your roof type and give you the data sheet to work from. Find your nearest store at www.prominentpaints.co.za.